Added TupleHasType class for template metaprogramming

This commit is contained in:
Vraiment 2017-07-30 23:44:28 -07:00
parent 315d032b3b
commit 3c3d45d94c

View File

@ -28,9 +28,9 @@
#include <utility>
#endif
#include <tuple>
#include <type_traits>
namespace SDL2pp {
/*
* This is code not to be used directly by users of SDL2pp.
@ -93,6 +93,25 @@ namespace Private {
template <typename T, typename... Tx>
using And = typename AndOperation<T, Tx...>::type;
#endif
/*
* Templated class to an specific type in a tuple, returns std::true_type if the
* tuple contains T, std::false_type otherwise.
*/
template <typename T, typename Tuple>
struct TupleHasTypeOperation;
template <typename T>
struct TupleHasTypeOperation<T, std::tuple<>> : std::false_type { };
template <typename T, typename U, typename... Tx>
struct TupleHasTypeOperation<T, std::tuple<U, Tx...>> : TupleHasTypeOperation<T, std::tuple<Tx...>> { };
template <typename T, typename... Tx>
struct TupleHasTypeOperation<T, std::tuple<T, Tx...>> : std::true_type { };
template <typename T, typename... Tx>
using TupleHasType = typename TupleHasTypeOperation<T, Tx...>::type;
}
}